/**
 * Copyright (c) 2011-2014 Felix Gnass
 * Licensed under the MIT license
 * http://spin.js.org/
 *
 * Example:
 var opts = {
 lines: 12,            // The number of lines to draw
 length: 7,            // The length of each line
 width: 5,             // The line thickness
 radius: 10,           // The radius of the inner circle
 scale: 1.0,           // Scales overall size of the spinner
 corners: 1,           // Roundness (0..1)
 color: '#000',        // #rgb or #rrggbb
 opacity: 1/4,         // Opacity of the lines
 rotate: 0,            // Rotation offset
 direction: 1,         // 1: clockwise, -1: counterclockwise
 speed: 1,             // Rounds per second
 trail: 100,           // Afterglow percentage
 fps: 20,              // Frames per second when using setTimeout()
 zIndex: 2e9,          // Use a high z-index by default
 className: 'spinner', // CSS class to assign to the element
 top: '50%',           // center vertically
 left: '50%',          // center horizontally
 shadow: false,        // Whether to render a shadow
 hwaccel: false,       // Whether to use hardware acceleration (might be buggy)
 position: 'absolute'  // Element positioning
 };
 var target = document.getElementById('foo');
 var spinner = new Spinner(opts).spin(target);
 */
;(function(root, factory) {
    if (typeof module == 'object' && module.exports) module.exports = factory(); // CommonJS
    else if (typeof define == 'function' && define.amd) define(factory); // AMD module
    else root.Spinner = factory(); // Browser global
}
(this, function() {
    'use strict';

    var prefixes = ['webkit', 'Moz', 'ms', 'O']; // Vendor prefixes
    var animations = {}; // Animation rules keyed by their name
    var useCssAnimations; // Whether to use CSS animations or setTimeout
    var sheet; // A stylesheet to hold the @keyframe or VML rules

    /**
     * Utility function to create elements. If no tag name is given,
     * a DIV is created. Optionally properties can be passed.
     */
    function createEl(tag, prop) {
        var el = document.createElement(tag || 'div');
        var n;

        for (n in prop) el[n] = prop[n];
        return el;
    }

    /**
     * Appends children and returns the parent.
     */
    function ins(parent /* child1, child2, ...*/) {
        for (var i = 1, n = arguments.length; i < n; i++) {
            parent.appendChild(arguments[i]);
        }

        return parent;
    }

    /**
     * Creates an opacity keyframe animation rule and returns its name.
     * Since most mobile Webkits have timing issues with animation-delay,
     * we create separate rules for each line/segment.
     */
    function addAnimation(alpha, trail, i, lines) {
        var name = ['opacity', trail, ~~(alpha * 100), i, lines].join('-');
        var start = 0.01 + i/lines * 100;
        var z = Math.max(1 - (1-alpha) / trail * (100-start), alpha);
        var prefix = useCssAnimations.substring(0, useCssAnimations.indexOf('Animation')).toLowerCase();
        var pre = prefix && '-' + prefix + '-' || '';

        if (!animations[name]) {
            sheet.insertRule(
                '@' + pre + 'keyframes ' + name + '{' +
                '0%{opacity:' + z + '}' +
                start + '%{opacity:' + alpha + '}' +
                (start+0.01) + '%{opacity:1}' +
                (start+trail) % 100 + '%{opacity:' + alpha + '}' +
                '100%{opacity:' + z + '}' +
                '}', sheet.cssRules.length);

            animations[name] = 1;
        }

        return name;
    }

    /**
     * Tries various vendor prefixes and returns the first supported property.
     */
    function vendor(el, prop) {
        var s = el.style;
        var pp;
        var i;

        prop = prop.charAt(0).toUpperCase() + prop.slice(1);
        if (s[prop] !== undefined) return prop;
        for (i = 0; i < prefixes.length; i++) {
            pp = prefixes[i]+prop;
            if (s[pp] !== undefined) return pp;
        }
    }

    /**
     * Sets multiple style properties at once.
     */
    function css(el, prop) {
        for (var n in prop) {
            el.style[vendor(el, n) || n] = prop[n];
        }

        return el;
    }

    /**
     * Fills in default values.
     */
    function merge(obj) {
        for (var i = 1; i < arguments.length; i++) {
            var def = arguments[i];
            for (var n in def) {
                if (obj[n] === undefined) obj[n] = def[n];
            }
        }
        return obj;
    }

    /**
     * Returns the line color from the given string or array.
     */
    function getColor(color, idx) {
        return typeof color == 'string' ? color : color[idx % color.length];
    }

    // Built-in defaults

    var defaults = {
        lines: 12,            // The number of lines to draw
        length: 7,            // The length of each line
        width: 5,             // The line thickness
        radius: 10,           // The radius of the inner circle
        scale: 1.0,           // Scales overall size of the spinner
        corners: 1,           // Roundness (0..1)
        color: '#000',        // #rgb or #rrggbb
        opacity: 1/4,         // Opacity of the lines
        rotate: 0,            // Rotation offset
        direction: 1,         // 1: clockwise, -1: counterclockwise
        speed: 1,             // Rounds per second
        trail: 100,           // Afterglow percentage
        fps: 20,              // Frames per second when using setTimeout()
        zIndex: 2e9,          // Use a high z-index by default
        className: 'spinner', // CSS class to assign to the element
        top: '50%',           // center vertically
        left: '50%',          // center horizontally
        shadow: false,        // Whether to render a shadow
        hwaccel: false,       // Whether to use hardware acceleration
        position: 'absolute'  // Element positioning
    };

    /** The constructor */
    function Spinner(o) {
        this.opts = merge(o || {}, Spinner.defaults, defaults);
    }

    // Global defaults that override the built-ins:
    Spinner.defaults = {};

    merge(Spinner.prototype, {
        /**
         * Adds the spinner to the given target element. If this instance is already
         * spinning, it is automatically removed from its previous target b calling
         * stop() internally.
         */
        spin: function(target) {
            this.stop();

            var self = this;
            var o = self.opts;
            var el = self.el = createEl(null, {className: o.className});

            css(el, {
                position: o.position,
                width: 0,
                zIndex: o.zIndex,
                left: o.left,
                top: o.top
            });

            if (target) {
                target.insertBefore(el, target.firstChild || null);
                target.className = "fade";
            }

            el.setAttribute('role', 'progressbar');
            self.lines(el, self.opts);

            if (!useCssAnimations) {
                // No CSS animation support, use setTimeout() instead
                var i = 0;
                var start = (o.lines - 1) * (1 - o.direction) / 2;
                var alpha;
                var fps = o.fps;
                var f = fps / o.speed;
                var ostep = (1 - o.opacity) / (f * o.trail / 100);
                var astep = f / o.lines;

                (function anim() {
                    i++;
                    for (var j = 0; j < o.lines; j++) {
                        alpha = Math.max(1 - (i + (o.lines - j) * astep) % f * ostep, o.opacity);

                        self.opacity(el, j * o.direction + start, alpha, o);
                    }
                    self.timeout = self.el && setTimeout(anim, ~~(1000 / fps));
                })();
            }

            return self;
        },

        /**
         * Stops and removes the Spinner.
         */
        stop: function() {
            var el = this.el;
            if (el) {
                clearTimeout(this.timeout);
                if (el.parentNode) {
                    var reg = new RegExp('(\\s|^)fade(\\s|$)');
                    el.parentNode.className = el.parentNode.className.replace(reg, ' ');
                    el.parentNode.removeChild(el);
                }
                this.el = undefined;
            }
            return this;
        },

        /**
         * Internal method that draws the individual lines. Will be overwritten
         * in VML fallback mode below.
         */
        lines: function(el, o) {
            var i = 0;
            var start = (o.lines - 1) * (1 - o.direction) / 2;
            var seg;

            function fill(color, shadow) {
                return css(createEl(), {
                    position: 'absolute',
                    width: o.scale * (o.length + o.width) + 'px',
                    height: o.scale * o.width + 'px',
                    background: color,
                    boxShadow: shadow,
                    transformOrigin: 'left',
                    transform: 'rotate(' + ~~(360/o.lines*i + o.rotate) + 'deg) translate(' + o.scale*o.radius + 'px' + ',0)',
                    borderRadius: (o.corners * o.scale * o.width >> 1) + 'px'
                });
            }

            for (; i < o.lines; i++) {
                seg = css(createEl(), {
                    position: 'absolute',
                    top: 1 + ~(o.scale * o.width / 2) + 'px',
                    transform: o.hwaccel ? 'translate3d(0,0,0)' : '',
                    opacity: o.opacity,
                    animation: useCssAnimations && addAnimation(o.opacity, o.trail, start + i * o.direction, o.lines) + ' ' + 1 / o.speed + 's linear infinite'
                });

                if (o.shadow) ins(seg, css(fill('#000', '0 0 4px #000'), {top: '2px'}));
                ins(el, ins(seg, fill(getColor(o.color, i), '0 0 1px rgba(0,0,0,.1)')));
            }
            return el;
        },

        /**
         * Internal method that adjusts the opacity of a single line.
         * Will be overwritten in VML fallback mode below.
         */
        opacity: function(el, i, val) {
            if (i < el.childNodes.length) el.childNodes[i].style.opacity = val;
        }

    });


    function initVML() {

        /* Utility function to create a VML tag */
        function vml(tag, attr) {
            return createEl('<' + tag + ' xmlns="urn:schemas-microsoft.com:vml" class="spin-vml">', attr);
        }

        // No CSS transforms but VML support, add a CSS rule for VML elements:
        sheet.addRule('.spin-vml', 'behavior:url(#default#VML)');

        Spinner.prototype.lines = function(el, o) {
            var r = o.scale * (o.length + o.width);
            var s = o.scale * 2 * r;

            function grp() {
                return css(
                    vml('group', {
                        coordsize: s + ' ' + s,
                        coordorigin: -r + ' ' + -r
                    }),
                    { width: s, height: s }
                );
            }

            var margin = -(o.width + o.length) * o.scale * 2 + 'px';
            var g = css(grp(), {position: 'absolute', top: margin, left: margin});
            var i;

            function seg(i, dx, filter) {
                ins(
                    g,
                    ins(
                        css(grp(), {rotation: 360 / o.lines * i + 'deg', left: ~~dx}),
                        ins(
                            css(
                                vml('roundrect', {arcsize: o.corners}),
                                {
                                    width: r,
                                    height: o.scale * o.width,
                                    left: o.scale * o.radius,
                                    top: -o.scale * o.width >> 1,
                                    filter: filter
                                }
                            ),
                            vml('fill', {color: getColor(o.color, i), opacity: o.opacity}),
                            vml('stroke', {opacity: 0}) // transparent stroke to fix color bleeding upon opacity change
                        )
                    )
                );
            }

            if (o.shadow)
                for (i = 1; i <= o.lines; i++) {
                    seg(i, -2, 'progid:DXImageTransform.Microsoft.Blur(pixelradius=2,makeshadow=1,shadowopacity=.3)');
                }

            for (i = 1; i <= o.lines; i++) seg(i);
            return ins(el, g);
        };

        Spinner.prototype.opacity = function(el, i, val, o) {
            var c = el.firstChild;
            o = o.shadow && o.lines || 0;
            if (c && i + o < c.childNodes.length) {
                c = c.childNodes[i + o]; c = c && c.firstChild; c = c && c.firstChild;
                if (c) c.opacity = val;
            }
        };
    }

    if (typeof document !== 'undefined') {
        sheet = (function() {
            var el = createEl('style', {type : 'text/css'});
            ins(document.getElementsByTagName('head')[0], el);
            return el.sheet || el.styleSheet;
        }());

        var probe = css(createEl('group'), {behavior: 'url(#default#VML)'});

        if (!vendor(probe, 'transform') && probe.adj) initVML();
        else useCssAnimations = vendor(probe, 'animation');
    }

    return Spinner;

}));